Although various psychomotor and cognitive tasks are widely utilized in studies assessing the effects of psychoactive drugs on performance, no study, to our knowledge, has systematically examined the effect of varying contingencies of reinforcement on human performance. In this context, a reinforcement contingency can be defined as an experimental condition in which some monetary rewards is paid upon completion of a particular behavior. In most studies, subjects perform tasks with no particular consequence for accurate performance or are paid some arbitrary amount for correct responding. This lack of attention to the effects of reinforcement contingencies on performance is somewhat surprising given the extensive animal literature reporting dramatic effects of manipulating reinforcement conditions on schedule-controlled behavior. Manipulating reinforcement contingencies on performance is an objective, measureable means of varying what is commonly referred to as motivation. Obviously, a person's level of motivation can be an important factor in determining the quality and quantity of their performance. The lack of standardizing a person's motivational level by holding constant contingencies of reinforcement can result in behavior that is subject to uncontrolled variation. A series of studies will examine the effects of manipulating reinforcement contingencies on human performance by differentially reinforcing task speed versus task accuracy. Subject testing began in 1990, and four separate experiments have been completed (N=21). Results indicate that, in general, subjects' behavior has not readily come under the control of the reinforcement contingencies. Further studies will be designed to determine what contingency conditions reliably control task performance.